1. The Field of the Invention
The present invention relates to hydrogel materials. The materials include a hydrogel polymer that incorporates ceragenin compound that controllably elute from the hydrogel polymer. The hydrogel materials may be formed into a contact lens.
2. The Relevant Technology
A hydrogel polymer is a polymer that can absorb and retain extremely large amounts of a liquid relative to its own mass. In deionized and distilled water a hydrogel polymer may absorb 500 times its weight (from 30-60 times its own volume). The ability of a hydrogel polymer to absorb water depends on the ionic concentration of the aqueous solution being absorbed. Saline solutions are less absorbed than distilled water. For example, a saline solution of 0.9% is absorbed by a hydrogel polymer on the order of 50 times the polymer's weight.
The total absorbency and swelling capacity are controlled by the type and degree of cross-linkers used to make the polymer. Hydrogel polymers are commonly made by polymerizing acrylic acid blended with sodium hydroxide in the presence of an initiator to form a poly-acrylic acid sodium salt (sometimes referred to as sodium polyacrylate).